Three-term Congresswoman Tulsi Gabbard of Hawaii, a member of both the Armed Services and Foreign Affairs committees, has proposed legislation that would prohibit any U.S. assistance to terrorist organizations in Syria as well as to any organization working directly with them. Equally important, it would prohibit U.S. military sales and other forms of military cooperation with other countries that provide arms or financing to those terrorists and their collaborators.

Gabbard’s “Stop Arming Terrorists Act”challenges for the first time in Congress a U.S. policy toward the conflict in the Syrian civil war that should have set off alarm bells long ago: in 2012-13 the Obama administration helped its Sunni allies Turkey, Saudi Arabia, and Qatar provide arms to Syrian and non-Syrian armed groups to force President Bashar al-Assad out of power. And in 2013 the administration began to provide arms to what the CIA judged to be “relatively moderate” anti-Assad groups—meaning they incorporated various degrees of Islamic extremism.

That policy, ostensibly aimed at helping replace the Assad regime with a more democratic alternative, has actually helped build up al Qaeda’s Syrian franchise al Nusra Front into the dominant threat to Assad.

The supporters of this arms-supply policy believe it is necessary as pushback against Iranian influence in Syria. But that argument skirts the real issue raised by the policy’s history. The Obama administration’s Syria policy effectively sold out the U.S. interest that was supposed to be the touchstone of the “Global War on Terrorism”—the eradication of al Qaeda and its terrorist affiliates. The United States has instead subordinated that U.S. interest in counter-terrorism to the interests of its Sunni allies. In doing so it has helped create a new terrorist threat in the heart of the Middle East.

The policy of arming military groups committed to overthrowing the government of President Bashar al-Assad began in September 2011, when President Barack Obama was pressed by his Sunni allies—Turkey, Saudi Arabia and Qatar—to supply heavy weapons to a military opposition to Assad they were determined to establish. Turkey and the Gulf regimes wanted the United States to provide anti-tank and anti-aircraft weapons to the rebels, according to a former Obama Administration official involved in Middle East issues.

Obama refused to provide arms to the opposition, but he agreed to provide covert U.S. logistical help in carrying out a campaign of military assistance to arm opposition groups. CIA involvement in the arming of anti-Assad forces began with arranging for the shipment of weapons from the stocks of the Gaddafi regime that had been stored in Benghazi. CIA-controlled firms shipped the weapons from the military port of Benghazi to two small ports in Syria using former U.S. military personnel to manage the logistics, as investigative reporter Sy Hersh detailed in 2014. The funding for the program came mainly from the Saudis.

A declassified October 2012 Defense Intelligence Agency report revealed that the shipment in late August 2012 had included 500 sniper rifles, 100 RPG (rocket propelled grenade launchers) along with 300 RPG rounds and 400 howitzers. Each arms shipment encompassed as many as ten shipping containers, it reported, each of which held about 48,000 pounds of cargo. That suggests a total payload of up to 250 tons of weapons per shipment. Even if the CIA had organized only one shipment per month, the arms shipments would have totaled 2,750 tons of arms bound ultimately for Syria from October 2011 through August 2012. More likely it was a multiple of that figure.

The CIA’s covert arms shipments from Libya came to an abrupt halt in September 2012 when Libyan militants attacked and burned the embassy annex in Benghazi that had been used to support the operation. By then, however, a much larger channel for arming anti-government forces was opening up. The CIA put the Saudis in touch with a senior Croatian official who had offered to sell large quantities of arms left over from the Balkan Wars of the 1990s. And the CIA helped them shop for weapons from arms dealers and governments in several other former Soviet bloc countries.

Flush with weapons acquired from both the CIA Libya program and from the Croatians, the Saudis and Qataris dramatically increased the number of flights by military cargo planes to Turkey in December 2012 and continued that intensive pace for the next two and a half months. TheNew York Timesreported a total 160 such flights through mid-March 2013. The most common cargo plane in use in the Gulf, the Ilyushin IL-76, can carry roughly 50 tons of cargo on a flight, which would indicate that as much as 8,000 tons of weapons poured across the Turkish border into Syria just in late 2012 and in 2013.

One U.S. official called the new level of arms deliveries to Syrian rebels a “cataract of weaponry.”And a year-long investigation by the Balkan Investigative Reporting Network and the Organized Crime and Corruption Reporting Project revealed that the Saudis were intent on building up a powerful conventional army in Syria. The “end-use certificate” for weapons purchased from an arms company in Belgrade, Serbia, in May 2013 includes 500 Soviet-designed PG-7VR rocket launchers that can penetrate even heavily-armored tanks, along with two million rounds; 50 Konkurs anti-tank missile launchers and 500 missiles, 50 anti-aircraft guns mounted on armored vehicles, 10,000 fragmentation rounds for OG-7 rocket launchers capable of piercing heavy body armor; four truck-mounted BM-21 GRAD multiple rocket launchers, each of which fires 40 rockets at a time with a range of 12 to 19 miles, along with 20,000 GRAD rockets.

The end user document for another Saudi order from the same Serbian company listed 300 tanks, 2,000 RPG launchers, and 16,500 other rocket launchers, one million rounds for ZU-23-2 anti-aircraft guns, and 315 million cartridges for various other guns.

Those two purchases were only a fraction of the totality of the arms obtained by the Saudis over the next few years from eight Balkan nations. Investigators found that the Saudis made their biggest arms deals with former Soviet bloc states in 2015, and that the weapons included many that had just come off factory production lines. Nearly 40 percent of the arms the Saudis purchased from those countries, moreover, still had not been delivered by early 2017. So the Saudis had already contracted for enough weaponry to keep a large-scale conventional war in Syria going for several more years.

By far the most consequential single Saudi arms purchase was not from the Balkans, however, but from the United States. It was the December 2013 U.S. sale of 15,000 TOW anti-tank missiles to the Saudis at a cost of about $1 billion—the result of Obama’s decision earlier that year to reverse his ban on lethal assistance to anti-Assad armed groups. The Saudis had agreed, moreover, that those anti-tank missiles would be doled out to Syrian groups only at U.S. discretion. The TOW missiles began to arrive in Syria in 2014 and soon had a major impact on the military balance.

This flood of weapons into Syria, along with the entry of 20,000 foreign fighters into the country—primarily through Turkey—largely defined the nature of the conflict. These armaments helped make al Qaeda’s Syrian franchise, al Nusra Front (now renamed Tahrir al-Sham or Levant Liberation Organization) and its close allies by far the most powerful anti-Assad forces in Syria—and gave rise to the Islamic State.

By late 2012, it became clear to U.S. officials that the largest share of the arms that began flowing into Syria early in the year were going to the rapidly growing al Qaeda presence in the country. In October 2012, U.S. officials acknowledged off the record for the first time to theNew York Timesthat “most” of the arms that had been shipped to armed opposition groups in Syria with U.S. logistical assistance during the previous year had gone to “hardline Islamic jihadists”— obviously meaning al Qaeda’s Syrian franchise, al Nusra.

Al Nusra Front and its allies became the main recipients of the weapons because the Saudis, Turks, and Qataris wanted the arms to go to the military units that were most successful in attacking government targets. And by the summer of 2012, al Nusra Front, buttressed by the thousands of foreign jihadists pouring into the country across the Turkish border, was already taking the lead in attacks on the Syrian government in coordination with “Free Syrian Army” brigades.

In November and December 2012, al Nusra Front began establishing formal “joint operations rooms” with those calling themselves “Free Syrian Army” on several battlefronts, as Charles Lister chronicles in his book The Syrian Jihad. One such commander favored by Washington was Col. Abdul Jabbar al-Oqaidi, a former Syrian army officer who headed something called the Aleppo Revolutionary Military Council. Ambassador Robert Ford, who continued to hold that position even after he had been withdrawn from Syria, publicly visited Oqaidi in May 2013 to express U.S. support for him and the FSA.

But Oqaidi and his troops were junior partners in a coalition in Aleppo in which al Nusra was by far the strongest element. That reality is clearly reflected in a video in which Oqaidi describes his good relations with officials of the “Islamic State” and is shown joining the main jihadist commander in the Aleppo region celebrating the capture of the Syrian government’s Menagh Air Base in September 2013.

By early 2013, in fact, the “Free Syrian Army,” which had never actually been a military organization with any troops, had ceased to have any real significance in the Syria conflict. New anti-Assad armed groups had stopped using the name even as a “brand” to identify themselves, as a leading specialist on the conflict observed.

So, when weapons from Turkey arrived at the various battlefronts, it was understood by all the non-jihadist groups that they would be shared with al Nusra Front and its close allies. A report by McClatchy in early 2013, on a town in north central Syria, showed how the military arrangements between al Nusra and those brigades calling themselves “Free Syrian Army” governed the distribution of weapons. One of those units, the Victory Brigade, had participated in a “joint operations room” with al Qaeda’s most important military ally, Ahrar al Sham, in a successful attack on a strategic town a few weeks earlier. A visiting reporter watched that brigade and Ahrar al Sham show off new sophisticated weapons that included Russian-made RPG27 shoulder-fired rocket-propelled anti-tank grenades and RG6 grenade launchers.

When asked if the Victory Brigade had shared its new weapons with Ahrar al Sham, the latter’s spokesman responded, “Of course they share their weapons with us. We fight together.”

Turkey and Qatar consciously chose al Qaeda and its closest ally, Ahrar al Sham, as the recipients of weapons systems. In late 2013 and early 2014, several truckloads of arms bound for the province of Hatay, just south of the Turkish border, were intercepted by Turkish police. They had Turkish intelligence personnel on board, according to later Turkish police court testimony. The province was controlled by Ahrar al Sham. In fact Turkey soon began to treat Ahrar al Sham as its primary client in Syria, according to Faysal Itani, a senior fellow at the Atlantic Council’s Rafik Hariri Center for the Middle East.

A Qatari intelligence operative who had been involved in shipping arms to extremist groups in Libya was a key figure in directing the flow of arms from Turkey into Syria. An Arab intelligence source familiar with the discussions among the external suppliers near the Syrian border in Turkey during those years told theWashington Post’sDavid Ignatius that when one of the participants warned that the outside powers were building up the jihadists while the non-Islamist groups were withering away, the Qatari operative responded, “I will send weapons to al Qaeda if it will help.”

The Qataris did funnel arms to both al Nusra Front and Ahrar al Sham, according to a Middle Eastern diplomatic source. The Obama administration’s National Security Council staff proposed in 2013 that the United States signal U.S. displeasure with Qatar over its arming of extremists in both Syria and Libya by withdrawing a squadron of fighter planes from the U.S. airbase at al-Udeid, Qatar. The Pentagon vetoed that mild form of pressure, however, to protect its access to its base in Qatar.

President Obama himself confronted Prime Minister Recep Tayyip Erdogan over his government’s support for the jihadists at a private White House dinner in May 2013, as recounted by Hersh. “We know what you’re doing with the radicals in Syria,” he quotes Obama as saying to Erdogan.

The administration addressed Turkey’s cooperation with the al Nusra publicly, however, only fleetingly in late 2014. Shortly after leaving Ankara, Francis Ricciardone, the U.S. ambassador to Turkey from 2011 through mid-2014, told The Daily Telegraph of London that Turkey had “worked with groups, frankly, for a period, including al Nusra.”

The closest Washington came to a public reprimand of its allies over the arming of terrorists in Syria was when Vice President Joe Biden criticized their role in October 2014. In impromptu remarks at Harvard University’s Kennedy School, Biden complained that “our biggest problem is our allies.” The forces they had supplied with arms, he said, were “al Nusra and al Qaeda and the extremist elements of jihadis coming from other parts of the world.”

Biden quickly apologized for the remarks, explaining that he didn’t mean that U.S. allies had deliberately helped the jihadists. But Ambassador Ford confirmed his complaint, telling BBC, “What Biden said about the allies aggravating the problem of extremism is true.”

In June 2013 Obama approved the first direct U.S. lethal military aid to rebel brigades that had been vetted by the CIA. By spring 2014, the U.S.-made BGM-71E anti-tank missiles from the 15,000 transferred to the Saudis began to appear in the hands of selected anti-Assad groups. But the CIA imposed the condition that the group receiving them would not cooperate with the al Nusra Front or its allies.

That condition implied that Washington was supplying military groups that were strong enough to maintain their independence from al Nusra Front. But the groups on the CIA’s list of vetted “relatively moderate” armed groups were all highly vulnerable to takeover by the al Qaeda affiliate. In November 2014, al Nusra Front troops struck the two strongest CIA-supported armed groups, Harakat Hazm and the Syrian Revolutionary Front on successive days and seized their heavy weapons, including both TOW anti-tank missiles and GRAD rockets.

In early March 2015, the Harakat Hazm Aleppo branch dissolved itself, and al Nusra Front promptly showed off photos of the TOW missiles and other equipment they had captured from it. And in March 2016, al Nusra Front troops attacked the headquarters of the 13th Division in northwestern Idlib province and seized all of its TOW missiles. Later that month, al Nusra Front released a video of its troops using the TOW missiles it had captured.

But that wasn’t the only way for al Nusra Front to benefit from the CIA’s largesse. Along with its close ally Ahrar al Sham, the terrorist organization began planning for a campaign to take complete control of Idlib province in the winter of 2014-15. Abandoning any pretense of distance from al Qaeda, Turkey, Saudi Arabia, and Qatar worked with al Nusra on the creation of a new military formation for Idlib called the “Army of Conquest,” consisting of the al Qaeda affiliate and its closest allies. Saudi Arabia and Qatar provided more weapons for the campaign, while Turkey facilitated their passage. On March 28, just four days after launching the campaign, the Army of Conquest successfully gained control of Idlib City.

The non-jihadist armed groups getting advanced weapons from the CIA assistance were not part of the initial assault on Idlib City. After the capture of Idlib the U.S.-led operations room for Syria in southern Turkey signaled to the CIA-supported groups in Idlib that they could now participate in the campaign to consolidate control over the rest of the province. According to Lister, the British researcher on jihadists in Syria who maintains contacts with both jihadist and other armed groups, recipients of CIA weapons, such as the Fursan al haq brigade and Division 13, did join the Idlib campaign alongside al Nusra Front without any move by the CIA to cut them off.

As the Idlib offensive began, the CIA-supported groups were getting TOW missiles in larger numbers, and they now used them with great effectiveness against the Syrian army tanks. That was the beginning of a new phase of the war, in which U.S. policy was to support an alliance between “relatively moderate” groups and the al Nusra Front.

The new alliance was carried over to Aleppo, where jihadist groups close to Nusra Front formed a new command called Fateh Halab (“Aleppo Conquest”) with nine armed groups in Aleppo province which were getting CIA assistance. The CIA-supported groups could claim that they weren’t cooperating with al Nusra Front because the al Qaeda franchise was not officially on the list of participants in the command. But as the report on the new command clearly implied, this was merely a way of allowing the CIA to continue providing weapons to its clients, despite their de facto alliance with al Qaeda.

The significance of all this is clear:by helping its Sunni allies provide weapons to al Nusra Front and its allies and by funneling into the war zone sophisticated weapons that were bound to fall into al Nusra hands or strengthen their overall military position, U.S. policy has been largely responsible for having extended al Qaeda’s power across a significant part of Syrian territory. The CIA and the Pentagon appear to be ready to tolerate such a betrayal of America’s stated counter-terrorism mission. Unless either Congress or the White House confronts that betrayal explicitly, as Tulsi Gabbard’s legislation would force them to do, U.S. policy will continue to be complicit in the consolidation of power by al Qaeda in Syria, even if the Islamic State is defeated there.